Pulley-block



(NModel.)

W. BILBY PULLEY BLOCK.

Patented-Aug. 2.1881.'

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N. PETERS4 mu-Liihugnpher. wmhinpm. u. C.

View of the same.

UNITED STATES PATENT OFFICE. i

WILLlAMfBILBY, OF PITTSBURG, PENNSYLVANIA.

PULLEY- BLocK.

SPEGIIFICAIION forming' part of LettersPatent No. 244,976, dated August 2, 1881. Application nieu Maren 5, 1881 (No modem To all whom it may concern.-

. Be it known thatl, WILLIAM BrLBY, Jr., of Pittsburg', in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Combined Pulley Block and Sheave; and I do hereby declare that the following is a full, clear, and exact description of the invention, which will enable others skilled in .the art to which it appertains to make and usev the same, reference bein ghad to the accompanying drawin gs,which form a part of this speciiication.

This invention relates to the construction of a combined pulleyblock and sheave, and it consists in a plain wood sheave having metal cheeks provided withinclosing flanges which project in over the sheave, and whose edges form guiding-cheeks for the rope, said wood sheave and metal cheeks being permanently riveted together and revolving together.

It also consists in the construction and combination of1 parts, substantiallyvr as hereinafter fully described and claimed.

Figure lis a side view of a pulley-block complete after my invention. `Figa 2 is an edge Fig. 3 is a transverse vertical section, enlarged, showing the combined sheave and block. Figui is a detail showing the relations of the anti-friction bearing and the pin. Fi-gs. 5 and 6 are modifications in the construction of the wood center.

The object of `my invention is to provide a pulley-block of cheap construction, light, and of as much wood and little metal as possible consistent with a due regard for strength and durability, to make it `easy running, and to provide against too rapid wear of therope if ofhemp or otherfiber, or of the sheave-center if wire-rope be used, and to bring all within a small and convenient compass.

A designates a circular block or sheave of wood (preferably lignum-vitte) having it face 'grooved, as shown at Figs.2 and 3. Me allic cheeks B, having the inwardly projecting anges b, are closely tted on the two sides of the sheave A, and the groove thus formed is circular at its bottom and has the sides rising Ahigh enough to completely receive the rope' and j prevent all possibility of its slipping off the sheavecenter, the metal cheeks B thus becoming a substitute for the usual wood block.

1 Cheeks B are fastened by the rivets c, which pass through the woodceuter and are headed in the countersunk holes of cheeks B. The combined block and sheave, thus constructed, may beset up iu the strap C, and, when provided with the hook D and eye E, is ready for use 5 but I prefer the anti-frictioncenter, which I construct in the following manner:

Two tlan ges, F, or bushings, each having the annular rib or projection d, are riveted around the center, through the wood, by means of the rivets e, arranged and xed like rivets o, the rivets c passingalso through the thin web of cheeks B, as shown. The cylindrical cavity still existing after the ribs d meet in the center of the sheave A, is previously filled with the anti-friction bearin g, consistin g of the annular heads fand the tive rollers g. Normally the rollers g form between them an aperture which just neatly receives the pin or spindle G, and the ou ter openings in the bushings F are slightly larger than the spindle, so that with all ordinary strains the weight is thrown upon the rollers g. rIhe peculiarity of this arrangement is that while the rollers do most of the work in friction, when they rise to the position shown in Fig. 4 the strain on the sheave exerted by the, rope and weight tends to force the spindie Gr up and actlike a wedge, and inthe ordinary construction the rollers gare thus forced asunder and the bearing damaged, if not destroyed; but by my construction the instant the spindle attempts to act as a wedge between the two upper rollers, g, it meetsthe solid bearing afforded by the bushing F, which then relieves the rollers of any destructive strain. Another resultis that while 'in ordinary rollerbushings the bearing of the sheave, being on the rollerssolcly, is short, and the sheave wabbles or oscillates with a tendency to foul the rope, in mine, on the contrary, every time the rollers `arrive at the position shown in Fig. 4, (which is live times in every revolution of the rollercage,) the sheave rests firmly by the solid bus-hing F on the spindle G, and the sheave will be more steady and keep the rope true.

In Fig. 5 I constructthe cheeks B as before, but continue the wood center A to the spindle, and have a plain bushing, F', as shown. For some purposes this answers very well, as the lignum-vitae absorbs the oil and yields it when IOO the, spindle gets dry, thus holding down the friction and making the running easy.

In Fig. 6 I have shown my invention as applied in part to wire-rope sheaves. I havehere the metal cheeks I3 and the wood center A; but I continue the flanges b inwardly till they meet, their sheave faces being concave to fit the rope. The remaining construction is as before. In this way I get all the advantages ot' lightness and superior strength.

The invention becomes of great advantage in the case of large pulley-blocks, or multiple blocks having several sheaves, on account of the lightness of construction. In all cases I get just as great strength and durability as a pulley-block can possess.

I do not lay claim to the broad idea of a sheave having a bushing containing a number of anti-friction rollers interposed between it and the pin or shaft, as such is old and well known.

.I claim as my invention- 1. The sheavc for pulley-blocks consisting ofthe wood centcrA, in combination with the metal cheeks or sides B, having flanges b, and projecting beyond the periphery of the sheave A, and rivets c, passing through both cheeks B and center A, substantially as described.

2. rIhe combination ot1 the anged bushings F F, roller-bearing f g, and spindle G, said bushings F having their external openings nearly in contact with spindle G, substantially as described, whereby tendency to excessive pressure throws bushings F into contact with thc spindle and relieves the rollers.

In testimony that I claim the foregoing as my own I have hereto ailixed my signature in presence of two witnesses.

WILLIAM BILBY, JR.

Witnesses:

T. J. MCTIGHE, F. A. PoLLocK. 

